Peripubertal Exposure to Glyphosate-Based Herbicides Promotes Histopathological Impairment in the Structure of the Diaphragm Muscle of C57BL/6 Mice

Abstract

Introduction.Glyphosate is an organophosphate herbicide most used in Latin America, with multisystemic effects, including the respiratory system. In this sense, the objective of this research was to analyze the muscle fibers and neuromuscular junctions (NMJs) of the diaphragm muscle of adult mice exposed to the glyphosate-based herbicide in the peripubertal period. Methods. Twelve male mice were used, divided into a control group (CTL, n = 6), which received water and a glyphosate-based herbicide group (GBH, n = 6), which received 50 mg/Kg/day of Roundup ® , both by gavage from 30 to 60 days. At 150 days, the animals were euthanized, and the diaphragm was collected for analysis of the muscle fibers through hematoxylin-eosin, Masson's trichrome and Picrossirius Red and the NMJs through the nonspecific esterases reaction. Results. Rounded fibers, hypereosinophilic sarcoplasm and enlarged nuclei were found predominantly in GBH. A reduction in body weight, an increase in muscle fiber morphometry, an increase in type III collagen, a decrease in the overlapping of type I and III collagen, and an increase in the area and greater diameter of the NMJs in GBH were observed. Conclusions. Peripubertal exposure to glyphosate-based herbicides showed morphological changes characteristic of muscle degeneration and altered the morphometry of muscle fibers and NMJs of the diaphragm of adult mice.